See, when I first got my Zephyr, there were two of us playing with trains at the same time. It would haven been inconvenient to make my father in law stop running his trains so I could program mine. A computer interface and JMRI wouldn’t help, as that’s no different than using a throttle to program, and standalone programmers like the SPROG were not around yet.
–Randy
It has been some years since I ran trains at home but I ran HO and some times 3/4 amp Micos so I could run maybe five locos at times. The Power Cab and DIY DCC amp meter showed me DCC current.
Rich
I have a couple of cheap Bachmann decoders whose address reverts to 3 if the loco encounters a short circuit & I use my NCE ProCab to reprogram the loco on the main while the rest of the crew keep running. Using it on the program track does shut down the layout.